: Partial support is requested for the third FASEB Summer Conference, "Mobile Elements in Mammalian Genomes" which will be held in Snowmass, CO, July 5-10, 2009. The objective of the meeting is to bring together a diverse group of investigators with a common interest in mobile DNA to discuss recent advances in how mobile elements have impacted and continue to influence the functional expression and evolution of mammalian genomes. The program comprises all aspects of mobile DNA including bioinformatics, biochemical, evolutionary, and population genetic studies on mammalian transposable elements, as well as work to exploit transposable elements for saturation mutagenesis and gene delivery. Comparative genomics provides strong evidence for mobile DNA amplification, repression and extinction in evolutionary time. Recently, detailed studies of the small inhibitory RNA pathway have provided strong evidence for derepression of mobile DNA in mutants of this pathway;the emerging interface of these two fields will be represented by a new session at this meeting. There will also be increased representation of studies that define a variety of roles for sequences derived from transposable elements in genome architecture and function. This timely conference will facilitate the sharing of exciting new findings, experimental challenges, and outstanding questions in this rapidly evolving field among students, post-doctoral trainees, and junior and senior principal investigators. PUBLIC HEALTH RELEVANCE: Mobile DNA has played, and continues to play a major role in shaping the structure and function of the mammalian genome. Retrotransposition deposits new copies of mobile DNA throughout the genome which can lead to gene disruption, modified expression of adjacent genes, and transduction of neighboring DNA;at the DNA level the resulting interspersed repeated sequences may give rise to novel regulatory networks, or provide a substrate for homologous recombination of mispaired sequences, leading to gene duplication, deletion, exon shuffling and chromosome translocation. Any one of the dynamic events caused by the presence and movement of mobile DNA in the human genome may lead to disease, including meiotic failure and infertility, inherited genetic diseases such as hemophilia and muscular dystrophy, and somatic diseases such as breast and colon cancer.